From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <482B8FE4.4020301@cn.fujitsu.com> Date: Thu, 15 May 2008 09:20:36 +0800 From: Li Zefan MIME-Version: 1.0 Subject: Re: [-mm][PATCH 1/4] Add memrlimit controller documentation (v4) References: <20080514130904.24440.23486.sendpatchset@localhost.localdomain> <20080514130915.24440.56106.sendpatchset@localhost.localdomain> In-Reply-To: <20080514130915.24440.56106.sendpatchset@localhost.localdomain> Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Balbir Singh Cc: linux-mm@kvack.org, Sudhir Kumar , YAMAMOTO Takashi , Paul Menage , linux-kernel@vger.kernel.org, Pavel Emelianov , Andrew Morton , KAMEZAWA Hiroyuki List-ID: Balbir Singh wrote: > Documentation patch - describes the goals and usage of the memrlimit > controller. > > > Signed-off-by: Balbir Singh > --- > > Documentation/controllers/memrlimit.txt | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff -puN /dev/null Documentation/controllers/memrlimit.txt > --- /dev/null 2008-05-14 04:27:30.032276540 +0530 > +++ linux-2.6.26-rc2-balbir/Documentation/controllers/memrlimit.txt 2008-05-14 18:35:55.000000000 +0530 > @@ -0,0 +1,29 @@ > +This controller is enabled by the CONFIG_CGROUP_MEMRLIMIT_CTLR option. Prior > +to reading this documentation please read Documentation/cgroups.txt and > +Documentation/controllers/memory.txt. Several of the principles of this > +controller are similar to the memory resource controller. > + > +This controller framework is designed to be extensible to control any > +memory resource limit with little effort. > + > +This new controller, controls the address space expansion of the tasks > +belonging to a cgroup. Address space control is provided along the same lines as > +RLIMIT_AS control, which is available via getrlimit(2)/setrlimit(2). > +The interface for controlling address space is provided through > +"rlimit.limit_in_bytes". The file is similar to "limit_in_bytes" w.r.t. the user memrlimit.limit_in_bytes > +interface. Please see section 3 of the memory resource controller documentation > +for more details on how to use the user interface to get and set values. > + > +The "memrlimit.usage_in_bytes" file provides information about the total address > +space usage of the tasks in the cgroup, in bytes. > + > +Advantages of providing this feature > + > +1. Control over virtual address space allows for a cgroup to fail gracefully > + i.e., via a malloc or mmap failure as compared to OOM kill when no > + pages can be reclaimed. > +2. It provides better control over how many pages can be swapped out when > + the cgroup goes over its limit. A badly setup cgroup can cause excessive > + swapping. Providing control over the address space allocations ensures > + that the system administrator has control over the total swapping that > + can take place. > _ > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org